venJava venJava - 5 months ago 35
Java Question

Difference in days between two dates in Java?

I need to find the number of days between two dates: one is from a report and one is the current date. My snippet:

int age=calculateDifference(agingDate, today);


Here
calculateDifference
is a private method,
agingDate
and
today
are
Date
objects, just for your clarification. I've followed two articles from a Java forum, Thread 1 / Thread 2.

It works fine in a standalone program although when I include this into my logic to read from the report I get an unusual difference in values.

Why is it happening and how can I fix it?

EDIT :

I'm getting a greater number of days compared to the actual amount of Days.

public static int calculateDifference(Date a, Date b)
{
int tempDifference = 0;
int difference = 0;
Calendar earlier = Calendar.getInstance();
Calendar later = Calendar.getInstance();

if (a.compareTo(b) < 0)
{
earlier.setTime(a);
later.setTime(b);
}
else
{
earlier.setTime(b);
later.setTime(a);
}

while (earlier.get(Calendar.YEAR) != later.get(Calendar.YEAR))
{
tempDifference = 365 * (later.get(Calendar.YEAR) - earlier.get(Calendar.YEAR));
difference += tempDifference;

earlier.add(Calendar.DAY_OF_YEAR, tempDifference);
}

if (earlier.get(Calendar.DAY_OF_YEAR) != later.get(Calendar.DAY_OF_YEAR))
{
tempDifference = later.get(Calendar.DAY_OF_YEAR) - earlier.get(Calendar.DAY_OF_YEAR);
difference += tempDifference;

earlier.add(Calendar.DAY_OF_YEAR, tempDifference);
}

return difference;
}


Note :

Unfortunately, none of the answers helped me solve the problem. I've accomplished this problem with the help of Joda-time library.

Answer

I would suggest you use the excellent Joda Time library instead of the flawed java.util.Date and friends. You could simply write

import java.util.Date;
import org.joda.time.DateTime;
import org.joda.time.Days;

Date past = new Date(110, 5, 20); // June 20th, 2010
Date today = new Date(110, 6, 24); // July 24th 
int days = Days.daysBetween(new DateTime(past), new DateTime(today)).getDays(); // => 34
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